Field
The present disclosure relates to a liquid discharge head that discharges liquid such as ink or the like, a liquid discharge apparatus, and a liquid discharge method.
Description of the Related Art
An inkjet recording head that performs recording by discharging a liquid such as ink or the like is representative of liquid discharge heads. In liquid discharge heads, volatile components in ink contained in the head evaporates from discharge orifices. This changes the concentration of color material in the ink near the discharge orifices, which is problematic in that unevenness of color occurs in images being recorded, viscosity increases near the discharge orifices, changing the speed of droplets being discharged, and droplet landing accuracy deteriorates, and so forth. A method is known to counter these problems, in which ink supplied to the liquid discharge head is circulated over a circulation path.
Japanese Patent Laid-Open No. 2008-142910 discloses an apparatus that prevents thickening of ink near discharge orifices that are in a state of not performing discharging by circulating ink. Further, PCT Japanese Translation Patent Publication No. 2002-533247 discloses an apparatus that cleans within a chamber by circulating ink.
However, the invention described in Japanese Patent Laid-Open No. 2008-142910 has a configuration where ink that has flowed into a head 11 from a first tank 12 passes through pressure chambers where piezoelectric elements have been disposed, and is recovered from the head 11, as illustrated in FIG. 7 of Japanese Patent Laid-Open No. 2008-142910. Moreover, the invention described in PCT Japanese Translation Patent Publication No. 2002-533247 has a configuration where ink that has flowed into a head 2010 from a lower container 2050 passes through chambers for discharging, and is recovered from the head 2010, as illustrated in FIGS. 4, 5, and 8 of PCT Japanese Translation Patent Publication No. 2002-533247.
Thus, the circulation configurations disclosed in both Japanese Patent Laid-Open No. 2008-142910 and PCT Japanese Translation Patent Publication No. 2002-533247 both involve ink that has flowed into the head passing through pressure chambers and being recovered from the head. In a case where the flow rate of circulation is increased, for example, in such a configuration, the ink passes through pressure chambers where the cross-sectional area is relatively smaller than the cross-sectional are of other channel portions, so the channel resistance is large at that portion, and pressure drop in the circulatory flow increases. The channel resistance at that portion can be reduced by enlarging the cross-sectional area of the pressure chambers, but larger pressure chambers affect discharge of ink, and further increase the size of the head.